The invention is in the field of multiple photoflash lamp units, such as flashcubes and planar arrays, adapted to be temporarily attached to a camera and capable of producing a plurality of flashes for taking a plurality of flash pictures.
Various designs and constructions have been proposed for multiple flash units. An example of a flashcube is described in U.S. Pat. No. 3,739,166 to R. M. Anderson. An example of a planar array is described in U.S Pat. Nos. 3,598,984 to S. L. Slomski and 3,598,985 to J. D. Harnden and W. P. Kornrumpf. Numerous types of cameras are provided with built-in sockets to which multiple flash units can be attached. When the flash lamps are close to the camera's lens axis, such as within a few inches, and especially with the small "pocket" cameras, there is a tendency for an undesirable "red-eye" effect to occur, i.e., a red coloring of the pupils of persons in the picture. This is caused because the flash of light enters the person's pupils and illuminates the retinas in the eyes at regions approximately in line with the optical axis of the camera's lens, so that the illuminated red coloring of the retina shows in the picture and causes the person's pupils to appear red. Extender posts are available for positioning flashcubes higher above the camera, and hence farther from the lens axis, for reducing the red-eye effect.